im wantin to start a SW tank and im not sure exactly what i have to get. i have a 20 gallon tank that i gonna to use. i already have the sand, sea salt, hydrometer and some Kent water treatment that helps maintain the pH. is there anything else that i need to get?

another question is would you recommend a protein skimmer or regular filter system. if the regular filter system is better, can i use one that is for freshwater or do i have to buy a salt water one?? and also...is it better to put the water in first then add the sand or the sand then the water??and does the protein skimmer/filter have to be goin during that process?

I would rinse the sand out if it is not live sand that is. also I would put the sand in first then use a funal and PVC pipe and add the water down the funal slowly try not to disturbe the sand. you will get some clowdyness that is ok. Then run you filter and pumps for about 3 days then get some damsels and let your tank cycle. It will tank about 6 weeks or so. you may lose some damsels but it will speed up the cycle that is ok.

When we did our 20 gallon saltwater we added the sand first, then the water. Its a good idea to put a bowl or something in there while you pour the water into the tank. That way you wont mix the sand all up. But make sure you rinse the sand out first.

As with cycling the tank, do you plan on having live rock? If you are you can cycle your tank with the live rock instead of fish. It is also safer for the fish should your ammonia levels get to high and kill your fish. It can take anywhere from 4 to 8 weeks for your tank to fully cycle.

And a protien skimmer is always good to help remove alot from the water.

Unless you only want those damels never use them to cycle a tank. They are a real pain to remove when they kill the fish you actually do want. People used to say to use damsels because they would flush them at the end of the cycle. Get a cup of established sand from a friends or lfs tank to seed yours with after the set up. Get some liverock and sit back for a few weeks. the longer the better.

Before I can give you anymore advice you will need to nail down exactly what type of tank you'd like to start with and or end up with. IE, is this a fish tank or a reef? Please read my sticky titled to saltwater owners for more info.